Some parents may have noticed that the less sleep their children get at night, the crankier they become. Well, now there is evidence to prove it.

Researchers from the Attention Behavior and Sleep Lab at the Douglas Research Center in Quebec, Canada found that helping children get more sleep at night is an effective way to improve their behavior and health.

Published in the journal Pediatrics, the study examined healthy, elementary school kids who had no known behavioral or academic issues. Half of the students went to bed almost an hour later than their usual bedtime, while the other half slept about 30 minutes longer on average.

Teachers, who were unaware of how much sleep each student received, reported on the change in their performance and behavior. The students who were sleep-deprived seemed easily frustrated and irritable, while those who slept longer were calmer and more alert in class.

Parents should be aware of how much sleep their kids are receiving each night. Try treating the value of sleep equal to eating healthy and staying active. According to the study, sleep is just as beneficial to the child’s behavior and overall health as good food and exercise.

If you’ve got some cranky toddlers out there, try making a new bedtime routine, and forcing those munchkins into bed a little earlier each night. They might fight it at first, but facts don’t lie, and an extra hour of snoozing time could make all the difference.